Case in point-
You know that situation- you're browsing the net, trawling facebook, and suddenly you see that your current partner has been posting on his/her ex's wall. A lot. Take a look- wow, their conversation seems pretty friendly, and missing in the guarded politeness that people tend to take on when going from "lover" to "acquaintance". They're not flirting, not really, but still- why so friendly?
And of course here comes the green-eyed monster
The main thing to remember now is that jealousy is not just for girls, and it is normal in any relationship that you value; Just don't let it steer your course.
People get into a relationship for one reason, and will also leave a relationship for one reason. That reason, is of course up to your own definition. Maybe you dated that girl cause she was crazy fun, or got with a guy cause his tattoos had a story and you wanted to be part of it. But in the same way, you may leave that tattooed man cause he doesn't respect you, or the girl dumps you cause you can't keep up and you get over her by drinking too much and having your friends knock sense back into you.
Either way, the Ex is an Ex for a reason- what attracted your partner to them did not outweigh what repelled them.
Keeping an Ex as a friend just means this : They are good to have as a friend. The operational word here being "Friend"
That means, you can get all the fun cool parts, like laughing and hanging out and discussing things you're both interested in, without having to go as deep as a romantic relationship would take you. Keep in mind, the way you communicate with a friend, even a very close one, is hugely different then with a romantic partner.
Basically, keeping an ex as a friend is like learning to play your favourite song on the guitar, without mastering any other chords or notes. You want just a couple of parts, not the whole damn thing.
Chicks- you can always write "I WON" in huge letters over a picture of you and your partner together and mail it to the ex. Or even better, a wedding invitation
Guys- dance your girl in front of that dude. She will see him, but cling to you)
(Ok no, don't do those things. You can imagine doing them, but really doing them would be letting jealousy steer your course- naughty naughty)
This also marks the beginning of a new category here- Advice(?)
So now this is becoming more then pretty words and pictures all strung in a row- you get to glimpse part of my inner workings now.